Means for dressing grinding wheels used for form grinding



D Oct. 25, 1938. H H. HARLEY ET AL 7 2,134,607

MEANS FOR DRESSING GRINDING WHEELS USED FOR FORM GRINDING 4 Sheets-Sheet 1 Filed Aug. 5. 1936 L y 0 m m w ,o n .r 9 v. "H... m i

ct. 25, 1938. H. H. HARLEY AL 9 5 MEANS FOR DRESSING GRINDING WHEELS USED FOR FORM GRINDING Filed Aug. 5. 1936 4 Sheets-Sheet 2 V I4 a v 8 l 30 1 f TQM A I I G I veritprsr 2,134,607 ELS USED FOR FORM GRINDING 4 Sheets-Sheet Z :hrwencom Af fomev.

owmm a W 5 mm mm VG m mm mm Q H'. H. HARLEY ET AL Filed Aug. 5, 1936 MEANS FOR DRESSING GRINDING WHE Oct. 25, 1938.

BINDING Oct. 25, 1938. H.. H. HARLEY ET AL MEANS FOR DRESSING GRINDING WHEELS USED FOR FORM G Filed Aug. 5, 1936 4 Sheets-Sheet 4 35 former and a stylusor tracer co -operating there- Figures '7 and 8 are cross-sectional views on 35 Patented Oct. 25, 1938 a a MEANS FOR DRESSING GRINDING WIIEELs USED FOR FORM GRINDING Herbert Henry Harley and James Yorston,

Coventry, England Application August 5, 1936, Serial No. 94,432

In Great Britain August 24, 1935 Claims. (01.125-11) This invention relates to an improved method is moved in one direction by the rectilinear moof and means for trueing or dressing grinding tion of the saddle while the other member is wheels used for form-grinding, such for example moved in a different direction by the rotary moas are employed in producing or finishingscrewtion of the lever. Alternatively, the dressing tool,

5 threads, annular ribbed members and the like, or wheelhead, may also have a combined rec- 5' and more particularly to grinding wheels in tilinear and rotary motion.

which the operative face is formed with a plu- In another and simpler form of wheel dressing rality of annular ribs and grooves. apparatus embodying this invention there are N Broadly stated, there are two methods which two slides movably mounted in a common guide, can be employed for dressing formed grinding one carrying the lever and the other-the former, 10 wheels of the kind referred to. In one case the and means are provided for imparting simultamovement of the diamond or the like is obtained neous relative movement to the said slides in by means of mechanism which generates the the guide at a given ratio depending upon the form required. The other methods involves the degree of reduction required. In this case the use of a former shaped as an enlarged and in dressing tool is carried direct by the short arm 15 some cases modified replica of the form to be of the lever and the stylus by the long arm, the produced, a stylus moving in contact with the ratio of the lengths of the two arms being prefiormer being connected with the dressing tool by erably equal to that of the relative movements suitable reduction mechanism. of the two slides. The present invention is concerned with the In the accompanying drawings, 20 I latter method and has for one of its objects to Figure 1 is a plan view of one form of the improvide improved means whereby relative moveproved wheel dressing apparatus.

ment between the former and stylus or tracer is Figure 2 is a longitudinal vertical sectional view reproduced on a reduced scale between the dressthereof on the line 11-11 of Figure 1. mg tool and the wheel. Figure 2A is a detailed sectional View on an en- 25 We are aware that for the purpose of dressing larged scale of part of the apparatus shown in the operative face of a grinding wheel it has al- Figure 2. y readybeen proposed to employ two compound Figures 3 and 4 are transverse sectional views slides, one carrying the dressing tool and the on the lines III-III and IV--IV respectively of 0 other the stylus or tracer, in combination with Figure 2 means for causing the two compound slides to F gu s 5 a 6 Views Similar to Figures move in' unison in proportionate relationshi 1 and 2 respectively showing an alternative con- In the method adopted according to the presstruction, Figure 6 being taken on the line VL-VI ent invention relative movement between the of Figure 5.

with is reproduced at a reduced ratio between the lines VII- 11 and VIIL-VIII respectively of the dressing tool and the grinding wheel by means Figure 6.

of a combination of rectilinear and rotary mo- F gures 9 and 10 are two Views taken a g t tions, angles to each other and illustrating a further The rectilinear and rotary components of the development of the invention. 40 combined movement may correspond respectively Throughout the drawings like parts are desigwith the length and depth of the profile of the h ed by simil r reference characters. former. Both of said components may be re- In e drawings, 2 represents a former, 3 a

duced to an equal extent at the dressing tool or Stylus tracer p ew t and 5 is at the grinding wheel, a t case may or th the wheel dressing tool the'movement of which in 45 ratio of reduction in the case of one component dressing t Operative face O the rinding Wheel may be less than in the case of the other comto the required form is controlled by the former 2. ponent. I In the arrangement shown in Figures 1, 2, 3 According to one construction of wheel dressand 4 the former 2 is fixed while the stylus 3 is ing apparatus embodying the present invention carried by the'long arm 5 of a lever-pivoted at 50' the stylus, or the former, is carried by a lever 6 in the upper side of a saddle I having a rectipivotally mounted in a sliding saddle so as to linear movement up a fiXeflv frame 8 in thehave a combined-rectilinear and rotary motion, direction of the length of'the said former. and the dressing tool, or the wheel'head, is car- The short arm 9 of the lever engages a block ried by a compound slide one member of which Ill adapted to slide in a longitudinal groove II 551' til four threads per inch at of the form it is required however, be adopted.

,or cutting edges of electric motor or in any other suitable manner and has one end rotatably mounted in the frame 8 so as to be axially immovable therein while the free end works in a nut 40 carried by the saddle.

In a further development of the invention the construction of the improved wheel dressing apparatus is considerably simplified, the dressing tool being carried directly by the short arm of the lever. The apparatus, as'shown in Figures 9 and 10, comprises two displaceable slides 4|, 42 mounted infa common guide 43 and provided with means such as the differential screw 44, for traversing them along the guide with a given ratio of relative displacement. The slide 4| carries the lever in the long arm of which the stylus or tracer 3 is mounted, whilst the short arm 9 carries the dressing tool 4; The slide 42 carries the former 2 which is an enlarged replica to dress. The ratio of the lengths of the arms of the lever and of the displacements of the two slides will depend upon the degree of reduction required at the dressing tool in each case. In the example shown this ratio is :1. That is to say, the former is ten times the size of the form to be dressed, the arm 5 of the lever is ten times'the length of the arm 9, and the movement of the slide 42 is ten times that of the slide 4|. Any other desired ratio may, The rectilinear component of the combined movement of the dressing tool is given by the displacement of the slide 4|, while the rotary component is given by the relative movements of the lever and former. Where the slides are operated by means of a differential screw, as shown, the dressing operation is carried out by rotating the screw which in the case of a 10:1 reduction willhave four threads per inch at the part engaging the slide 42 and fortythe part engaging the slide 4|. A biasing spring 45 secured to the slide 4| and acting on the lever serves to maintain the stylus in contact with the former.

It is to be understood that any other suitable means than a differential screw may be employed for moving the slides 4| and 42.

The invention in any of the forms above described is equally applicable to the dressing or forming of grinding wheels of the kind described in British Patent No. 216,507 in which the grinding wheel has a plurality of annular serrations progressively increasing size, and to the dressing or forming of grinding wheels of the kind described in British Patent No. 239,859 in which the grinding wheel has a plurality of annular grinding serrations or cutting edges so formed thereon as to provide spaces between the grinding wheel and the convolutions of the threaded member.

1. Apparatus for dressing the operative face of a grinding wheel, comprising a former, a lever, a stylus carried by one arm of said lever and adapted to co-operate with said former, a slide carrying said lever and capable of rectilinear motion, a dressing tool and means operated by the slide and the other arm of said lever whereby the movement of the stylus in traversing the former is transmitted dressing tool.

2. Apparatus for dressing the operative face of a grinding wheel, comprising a former, a lever, a stylus carried by one arm of said lever and adapted to co-operate with said former, a saddle carrying the lever and having a rectilinear motion, a dressing tool'an-d a compound slide carrying said tool, one member of said slide being movable in one direction at a reduced ratio by the rectilinear motion of the saddle and the other member of said slide being simultaneously movable in another direction at a reduced ratio by the other arm of said lever.

3. Apparatus for dressing the operative face of ,a grinding wheel, comprising a former, alever, a stylus carried by one arm of said lever and adapted to co-operate with said former, a saddle carrying the lever and having a rectilinear motion, a dressing tool and a compound slide carrying said tool, a drum adapted to be turned about its axis by the other arm of said lever and to move one member of said slide at a reduced ratio inone direction, and means operated by the rectilinear motion of the saddle to move the other member of said slide at a reduced ratio simultaneously in another direction.

4. Apparatus for dressing of a grinding wheel, comprising a former, a-lever, a stylus carried by one arm of said lever and adapted to co-operate with said former, a saddle carrying the lever and having a rectilinear motion, a dressing tool and a compound slide carrying said tool, means operated by the other arm of said lever for moving one member of said slide at a reduced ratio in one direction and a spindle adapted to be turned about its axis by the rectilinear motion of the saddle for moving the other member of the slide at a reduced ratio simultaneously in another direction.

5. Apparatus for dressing the operative face of a grinding wheel comprising a former, a lever, a stylus carried by one arm of said lever and adapted to co-operate with said former, a slide carryingthe lever, a slide carrying the former, a dressing tool operated by the other arm of said lever, and means for imparting a differential rectilinear motion to said slides whereby the movement of the stylus is reproduced on a reduced scale by the dressing tool.

HERBERT HENRY HARLEY. JAMES YORSTON.

the operative face 7 at a reduced ratio to the 

